Katie Denise Oxley Thomas, who was considered healthy and liked to run marathons, died on Jan. 4, the report said. She is the 42nd Californian under the age of 65 to die from the flu, the paper reported.

“I can tell you that she seemed absolutely fine on New Year’s Eve and called a friend Tuesday morning saying that she had a sore throat, and by Wednesday she was in the ICU,” her sister told the Mercury News.

“The doctor was saying that he had never seen anything like this, and it was not supposed to happen,” she said.

The family asked for a private autopsy. Her father believes she had gotten the flu shot, KGO reported.

Thomas had three children from 7 to 17.

Flu is now widespread in every state except Hawaii, but the good news is the season appears to already be peaking.

It’s been a rough few weeks: Hospitals have set up tents to handle patient overflow. Doctors are putting in double and triple shifts. Ambulances have been sidelined while paramedics waited to drop off patients.

“This morning, I couldn’t stand up. I was really weak,” said Margaret Shafer, who went to a Seattle emergency room this week after a bout with the flu was followed by pneumonia.

But an update out Friday from the Centers for Disease Control and Prevention shows patient traffic for flu is no longer skyrocketing the way it was in December.

Still, flu is unpredictable. “I don’t know where it will end up,” she added.

Many flu seasons don’t really get going until around Christmas and don’t crescendo until February. That’s how last year’s flu season played out. This season got off to an early start and cases surged over the holidays.